ResearcherID - CLICK HERE Scientific Journal Impact Factor (SJIF-2020) - CLICK HERE

THE STUDY OF MODIFICATIONS OF GENOMIC DNA IN ENDOTOXEMIA

Trofimov A.V., Trofimov V.A., Sidorov D.I., Kadimaliev D.A., Vlasov A.P.

Abstract: Background & objectives. Endogenous intoxication and, as a consequence, the development of multi-organ failure are extreme forms of the pathological process and require immediate and radical repairing, therefore, the study of the molecular mechanisms of the pathogenesis of endogenous intoxication syndrome is a topical issue. The aim of the study is to look into the DNA modifications during endotoxic "pollution" of the body and to understand the mechanisms of development of dysregulation processes mediated by structural changes in DNA. Methods. The rate of endogenous intoxication was assessed by determining the generally accepted laboratory-clinical and biochemical parameters. The mononuclear cell fraction was collected by gradient centrifugation on Ficoll-Paque™ (ρ=1,077). The isolation of DNA from blood mononuclear cells was performed by using Laura-Lee Boodram. UV-spectroscopic assays of DNA solutions were carried out using a spectrophotometer UV-3600 Shimadzu (Japan). The IR Fourier spectra of DNA preparations were recorded on IRPrestige-21 SHIMADZU spectrometer (Japan) in the range of 400 cm-1 - 4000 cm-1. Interpretation & conclusions. The paper is concerned with the study of changes in biochemical composition and structure of genomic DNA of mononuclear cells of venous blood in patients with endogenous intoxication. The FT-IR spectra of genomic DNA of patients’ venous blood mononuclear cells reveal that the band at a frequency of 1337 cm-1, characterising the fluctuations of CH2-group and sugar-base bonds, shifts to a higher frequency. The absorption band at 1491 cm-1, reflecting the movement of purine atoms and corresponding to –C=N guanine bond, becomes wider and has a more pronounced character. The absorption intensity increases at a frequency of 863 cm-1, characteristic of the type of twisting in N-type sugars. The intensity of the band 1086 cm-1, capturing the symmetric vibrations of the O=P=O stroma bonds decreases. The corresponding alterations in the spectrum point to changes in the mutual orientation of DNA phosphate groups, which is consequent to the topical untwisting of the double helix, redistribution of hydrogen bonds, the appearance of bends on it, resulting in changes in DNA spatial structure, and the increased proportion of DNA in the A-form. UV spectra of the DNA of the experimental samples showed a slight shift of the maximum and a small hyperchromic effect. The observed changes in the spatial structure of DNA may be attributed to the accumulation (penetration) of products in the DNA microenvironment, including those of toxic ones, formed due to impaired balance of biochemical reactions during intoxication. In its turn, changes in the conformation of DNA can be the cause of disorders of genetic processes, including those of gene expression and, as a consequence, lead to the development of dysregulation processes in patients’ bodies. Key words: endogenous intoxication, DNA configuration, DNA conformation, Fourier infrared spectroscopy, UV spectroscopy, reactive oxygen intermediate, lipid peroxidation.

FULL TEXT